The aim of this protocol is to determine the clinical safety and efficacy of the excimer laser system in patients with coronary artery disease. Specific goals are 1)to determine the adequacy of the procedure alone in reducing obstructive atherosclerotic lesions of the coronary arteries as determined by repeat angiography at six months, and 2)to determine the adequacy of excimer laser angioplasty in bypass graft recanalization.